1. Field of the Invention
The present invention provides isolated, purified, and recombinant forms of gluten-degrading proteases and methods for their use in degrading gluten in food. The invention therefore relates to the fields of biology, food preparation, medicine, and molecular biology.
2. Description of Related Disclosures
Celiac disease, also known as celiac sprue, and dermatitis herpetiformis (“DH”) are autoimmune diseases (and may be different manifestations of the same disease), and gluten sensitivity is a condition (collectively, celiac disease, DH, and gluten sensitivity are referred to herein as “gluten intolerance”) triggered by dietary gluten, a storage protein found in wheat and other cereals. Patients concerned with a potential for gluten intolerance may be advised or choose on their own to refrain from consuming gluten in any amount. Because gluten is a common protein in food, however, patients find it very difficult to avoid gluten and frequently experience relapse due to inadvertent disclosure.
U.S. Pat. No. 7,303,871 describes therapies decreasing adverse effects of gluten ingestion, which involve pre-treatment of gluten-containing food with a protease as well as the use of orally administered proteases to degrade gluten contemporaneously with its ingestion. U.S. Pat. No. 7,320,788 describes admixtures of proteases useful in these therapies, including an admixture of a prolyl endopeptidase (PEP), such as Sphingomonas capsulata PEP, and a glutamine endoprotease, such as EPB2 from barley. One such admixture formulated for oral administration and composed of recombinant forms of the barley EPB2 and the S. capsulata PEP (termed, respectively, ALV001 and ALV002; see PCT Pub. Nos. 2008/1115411 and 2008/115428) is currently in clinical trials. Each of the aforementioned patents and patent publications is specifically incorporated herein by reference.
To be effective upon oral administration, a protease must be active or, if in a zymogen form, activate and remain active long enough to degrade any gluten present into non-immunogenic fragments. The immunogenic peptides can be relatively small (˜10 amino acids) and are contained, often in multiple copies, in very large proteins. The conditions in the gastrointestinal tract are harsh, and any exogenously added protease is typically degraded, and so rendered inactive, quickly. Accordingly, there remains a need in the art for proteases useful in the treatment of gluten intolerance. The present invention meets that need.